Industrial electrolyzers such as those intended for the production of hydrogen and oxygen by the electrolysis of water are formed of a stack of a very large number of elemental electrolytic cells, this stack being held between two end plates by tie rods, and the whole being generally placed in an enclosure the inside of which is pressurized and brought up to a high temperature.
In order to avoid on the one hand leakage through the seals between the cells in the event of insufficient tightening of the tie rods, and on the other hand flow of these seals in the event of excessive tightening, it is necessary to exert upon each tie rod adequate tightening, neither too light nor too heavy. Furthermore in order to avoid an opening at the level of the seals it is necessary to keep the two end plates quite parallel and therefore consequently to have uniform tightening of the whole of the tie rods.